Jinggangmycin-induced NlPR-L and NlABD4-L genes regulate fecundity in the brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae).

The brown planthopper (BPH), Nilaparvata lugens (Stål), is a typical insecticide-induced resurgence rice pest that causes severe damage to rice in Asian countries. Previous studies have shown that the fungicide Jinggangmycin (JGM), used to control rice sheath blight disease, can stimulate BPH fecundity; however, the molecular mechanism remains to be further explored. In this study, based on transcriptomic analysis, we found that the PI3K-Akt signaling pathway was significantly enriched in BPH after feeding on JGM-treated rice, where the NlPR-L and NlABD4-L genes were significantly upregulated. We further investigated the physiological functions of NlPR-L and NlABD4-L by RNAi, and the results showed that silencing of NlPR-L and NlABD4-L markedly prolonged the developmental period of nymphs and significantly influenced nymph feeding behavior. Moreover, the NlPR-L and NlABD4-L were specifically expressed in female adults' ovaries. Knockdown of NlPR-L and NlABD4-L in the nymphal stage significantly reduced the antioxidant enzyme activity and gene expression levels in adults and inhibited female ovary development, reduced the expression levels of NlVg and NlVgR, shortened the pre-oviposition and oviposition period, and reduced female reproduction. The current study revealed the physiological functions of NlPR-L and NlABD4-L in the fecundity of BPH and demonstrated that the JGM stimulated BPH fecundity by altering the PI3K-Akt signaling-related genes. These results contribute to an understanding of JGM-induced enhanced feeding preferences, antioxidant profile, and reproduction, offering novel insights for the control of BPH and providing a new strategy for comprehensive management.